1. Field of the Invention
The present invention relates to a method of constructing a magnetic head for a hard disk drive.
2. Description of Related Art
Hard disk drives contain a magnetic disk which spins relative to an actuator arm assembly. At the end of the actuator arm is a magnetic head which can magnetize and sense the magnetic field of the disk. The head has a coil wrapped around a magnetic core. The core has a pole that is separated from a magnetic return path by a gap. The gap in a conventional head is kept relatively narrow to maintain the strength of the magnetic flux between the pole and return path.
The surface of the disk is magnetized in one of two opposite directions parallel with the radial axis of the disk. A change in direction is typically interpreted as a binary 1. Two consecutive readings in the same direction are treated as a binary 0. Magnetizing the surface of the disk parallel to the radial axis is commonly referred to as longitudinal recording.
There has been developed magnetic heads which have a relatively large separation between the pole and the magnetic return path. Such an arrangement causes the magnetic flux of the head to flow through the disk in a direction perpendicular to the radial axis. The material of the disk therefore becomes magnetized in a direction perpendicular to the radial axis. Magnetizing across the thickness of the disk is commonly referred to as vertical recording. Because magnetization is occurring through the disk thickness, instead of across the disk surface, vertical recording can potentially provide higher data densities than longitudinal recording techniques.
Magnetic heads are typically constructed to create an air bearing between the head and the surface of the disk. The air bearing prevents contact between the head and disk surface, and wear on the two members. Vertical recording heads create a longer flux path than conventional longitudinal recording heads. The air bearing between the head and the disk further increases the flux path. For vertical recording, it is desirable to provide a head that is in contact with the spinning disk. Unfortunately most conventional magnetic heads are heavy and thus cause excessive stiction and wear when used in contact recording.
U.S. Pat. No. 5,041,932 issued to Hamilton and assigned to Censtor Corp., discloses a magnetic head that is light enough (approximately 1.5 milligrams) to allow contact recording without excessive wear on the disk or head. Consequently, the Censtor head could be potentially used for vertical recording. The Censtor head is constructed with processes similar to constructing an integrated circuit, including steps of plating metal and sputtering dielectric material to create a conductive coil that spirals around a magnetic core. Although the Censtor magnetic head is lightweight, it is also very expensive to produce. It would therefore be desirable to provide a magnetic head that is inexpensive to produce and can be used for vertical recording.